Boat moves by surface tension

‘ ‘ ‘ Pitt researchers have designed a boat that moves the same way insects skate on water and… ‘ ‘ ‘ Pitt researchers have designed a boat that moves the same way insects skate on water and operates without the use of sails, motor or paddles. ‘ ‘ ‘ The developments might eventually be used in robots and microsurgery. ‘ ‘ ‘ Inspiration for the boat came to Sung Kwon Cho, Pitt senior researcher and professor of mechanical engineering and materials science, after he read research conducted at MIT on the aquatic motion of Pyrrhalta beetle larvae. ‘ ‘ ‘ Dr. David Hu was part of the team studying the beetles. He said that the researchers watched how the insects landed and moved on water surfaces. ‘ ‘ ‘ Sang Kug Chung, a Pitt engineering doctoral student who assisted with the project, elaborated. ‘ ‘ ‘ ‘The larva is a very poor swimmer usually, but as he swims he bends his back, changing the surface tension from front to rear,’ said Chung. ‘ ‘ ‘ Arching its body to upset the equilibrium of surface tension, the beetle pulls itself through the water. ‘ ‘ ‘ Using a team with Chung and Kyungjoo Ryu, another Pitt engineering doctoral student, Cho designed a boat that changes surface tension direction like the larvae. ‘ ‘ ‘ Chung described the method used to propel the small boat forward. ‘ ‘ ‘ ‘We knew how to change the direction by using electrostatic force,’ said Chung. ‘ ‘ ‘ Chung said that an electrode attached to a 2-centimeter long prototype boat emitted a surge to change the rear surface tension direction and propel the boat at roughly 4 millimeters per second. ‘ ‘ ‘ The electrode is coated in a hydrophobic polymer that, when charged, becomes attracted to water, changing the balance of the water’s forces and pushing the boat forward. ‘ ‘ ‘ A second electrode served as the rudder. ‘ ‘ ‘ Researchers said that future models may be able to reach speeds of 10 centimeters per second. ‘ ‘ ‘ The new method uses a fraction of the power required by older systems with moving parts. ‘ ‘ ‘ ‘ It could be powered by battery, radio waves or solar power, and could be best used for small robots and boats that monitor water quality. ‘ ‘ ‘ Systems powered by surface tension should have longer life expectancies than models with propellers. ‘ ‘ ‘ Chung called the research ‘very exciting,’ and elaborated upon its use. ‘ ‘ ‘ ‘We can use this for small boats with camera lenses which fit in small areas where larger boats cannot go,’ said Chung. ‘ ‘ ‘ He also said that the research might eventually benefit the medical field. ‘ ‘ ‘ ‘Later, we could possibly use this with microsurgery,’ said Chung. ‘ ‘ ‘ Hu said that the MIT research team attempted to build a watercraft using a methodology similar to that of the Pitt team. ‘ ‘ ‘ ‘We tried to build a few versions which deformed the water surface,’ said Hu. ‘ ‘ ‘ Hu said that Cho’s team is the first to use electricity to accomplish the task. ‘ ‘ ‘ ‘What they have done is a very interesting concept,’ said Hu. ‘They are using electricity to bend surface tension.’ ‘ ‘ ‘ Cho was unavailable for comment as he was in Sorrento, Italy preparing to present the team’s findings at the 2009 Micro Electro Mechanical Systems conference.